Apparatus for using telephone-subscribers&#39; loops for transmission and reception of broadcasting



1930. G. o. SQUIER APPARATUS FOR USING TELEPHONE SUBSCRIBERS' LOOPS FOR TRANSMISSION AND RECEPTION OF BROADCASTING Filed July 17, 1926 IN VEN TOR his ATTORNE i- Patented 7,

UNITED STATES PATENT OFFICE GEORGE O. SQ'UIER, OF WASHINGTON, DISTRICT 01: COLUMBIA urnnarus son usme' mnnrnonn-susscarsms LOOPS ron TRANSMISSION AND nncnrrxon or saonncns'rme Application filed July 17,'

This invention relates to'a method and means of impressing radio frequency energy 7 on the individual loops of-standard telephone circuits.

One of the objects of this invention is the provision of a new and novel combination of elements by means of which radio frequency energy in the form popularly known as broadcasting is impressed on each of the sub- 10 scribers loops of a telephone system, and is received when desired, at any particular subscribers station.

Another object of this invention is the provision of a combination of elements for the simultaneous production and transmission over the same telephone subscribers loops, of radio frequency and audio frequency eni nother object of this invention is the provision of a system of this type by means of which energy maybe delivered to telephone subscribers loops in a plurality of wave lengths, which may be selectively received at each or all of the subscribers stations.

A still further object successfully sought by this invention is the combination of elements by means of which, if desired, a single frequency current may be delivered to each or all of the subscribers loops of a telephone system, and detected and received by a single frequency receiver. 7

It is also an object of this invention to secure the above mentioned results without in any way interfering with the ordinary point to point conversation over the sub scribers loops.

It is also an object of this invention to so associate the radio frequency equipment with the telephone equipment so as to require no alterations in the existing equipment, but merely relatively simple additions thereto.

,It is also an object of this invention to utilize as the means for impressing radio fre- 1 quency energy on the subscribers loops, one of the pairs of wires disposed within the usual telephone cable with these loops.

These and many other objects which will be apparent in the following description, are

1926. Serial No. 123,080.

sought and obtained by the apparatus to be entertainment so that charges could be made therefor. As far as I am aware, no successful system has been devised whereby these programs could be distributed from a central station to known subscribers so that fixed charges could be made for-this service. I

have, therefore, devised a relatively simple system which is adapted to be associated with the standard'telephone equipment as it is now known, without in any way impairing the usual point'to point efficiency of this system. It has been found in actual practice 'that the telephone equipment as provided in the dwelling houses of the subscribers, is not in use for more than thirty minutes out of each\twenty-four hours. It willbe apparent then; that since there are approximately twelve million of these subscribers stations,

the vast majority of the telephone equipment remains idle during the greater part of the day. It is one of the objects of my invention to provide a system of broadcasting which may be readily associated with this equipment so that it may be kept in use for a greater part of the day than is now possible.

It will be evident that since in the modern telephone system as it is now known, if these programs could be supplied to the users, a suitable charge could be made therefor.

Since broadcasting is, inefiect, one way telephony, a very simple-equipment would be necessary for the reception of broadcast- 9 ing programs at the subscribers stations, and that it would only be necessary to provide transmitting equipment at the central station. I have therefore devised a very simple system for accomplishing thus) results. I

I draw particular attention to the fact that in the present systems utilized by the telephone companies for transmitting radio frequency energy over thelr cable systems, considerable effort is made to keep the radio frequenc energy out of the subscribers loops. n the contrary, in my invention I introduce directly into the subscribers loops, the broadcasting programs in the form of radio frequency energy.

Referring to the drawing, I have shown dia rammatically, three radio broadcastlng stu ios, 1, 2 and 3, the particular form, arrangement and construction of WlllCh I am not concerned with, since any suitable equipment for transforming the sounds to be transformed into electrical energy may beused. I have shown diagrammatically, in the output leads from these studios, variable condensers 4, and inductances 5 for tuning the output circuits of the broadcasting equipment. I do not, however, desire to be limlted to this illustration, since it is given to illustrate the principles of my invention rather than the physical embodiment thereof, the whole purpose of this equipment being to transform the entertainment in whateven form it may be, into suitable radio -frequency energy, which is delivered to the inductances 5 and thence to the inductances 6, connected in the antenna 7, which is grounded through the variable capacity 9, at 8. I do not desire to be limited to the transformer method of connecting the studios to the antenna, since any suitable connecting means is contemplated. In actual practice, I 1n tend that the antenna 7 shall consist of a single pair of wires, such as usually form a subscribers loop. The modern telephone cable, which I have illustrated at 10, comprises a plurality of pairs of wires 11, each pair connecting the central station with one of the subscribers, as is well known in the art. For the antenna, I find it desirable to select a pair of wires centrally located with respect to the other wires in the telephone cable. To further illustrate my invention, I have shown one pair of wires 12, extending into the subscribers station indicated generally at 13, which comprises the ringing bells 14, the large capacity condenser 15 for transmitting the audio frequency energy in this circuit, the usual telephone transformer 16, receiver 17, microphone 18', and hook switch 18. This is the usual and standard. equipment as now supplied to each subscriber. Across the terminals of the subscribers loop, I have connected in series, two small con-. densers 19 and 20, of suitable capacity for passing radio frequency energy. I have "shown diagrammatically, radio receiving set 22, connected between the condensers by means of the wires 21, and grounded in any suitable manner as at 23. I have not shown in detail, the construction of-the radio rewill be apparent from the foregoing description, but it may be stated that the antenna 7 may be tuned to the desired wave length to be transmitted, by means of the capacity 9, or other suitable tuning element, and the radio frequency energy from the studios may be impressed upon the antenna through the transformers 5, 6. Radio-frequency energy is then transmitted into the cable over the antenna 7, and thence to all of the pairs of wires within the cable 10. For example, in,

a telephone cable containing fifty telephone subscribers loops, w may consider the central loop selected as the transmitting antenna to be broadcasting radio programs to the other forty-nine loops Within the leadcovered cable. The currents introduced in these loops may then be interpreted in the home of each or all of the subscribers who are provided with receiving equipment, and W1tl10l1l3 111 any way interfering with the usual point to point communication. It will be at once apparent that the antenna 7 will be very efficient in its operation, since the maximum distance which it must transmit the radio frequency energy through space will not, in the usual practice, exceed one inch, and since the telephone cable is leadcovered, it will be apparent that no losses Wlll occur by straying electric fields.

Where only one studio is used for broadcasting, the programs may be sent out on a single constant wave length and each subscrlber may be provided with a standard receiver adapted only tobe operated at this one frequency. The receiving equipment then becomes exceedingly simple, and will require vmerely the turn of a switch to place it in and out of operation. I also contemplate that where desired, and as shown in the drawings, a plurality of studios may be associated with any one antenna, each emitting energy at a different Wave length. In this case the receivers may then be constructed torespond to this plurality of wave lengths, and a very slmple control means will be necessary to make it possible for the subscriber to select the desired program. It will be evident that the central station may be utilized for housmg the studios, or it will be apparent that programs may be secured at distributed points, such as hotels, public meeting houses, etc., as is now the common practice, and transmitted to the central station in the usual manner, where it may be impressed upon the antenna 7. i

I also contemplate that in the event of radio transmission of motion pictures, that even this service could be supplied by the central station over the subscribers loops to those subscribers whose stations are equipped with the necessary apparatus.

It should be noted that the telephone company would be able to keep a check on those subscribers using this service merely by requiring that standard equipment, prepared by them, be used, and that any servicing of this equipment wouldbe handled by'them, as

is the practice in connection with the present point to point communicating system.

Aside fromthe advantages and results which are readily apparent from the foregoing description, it may be noted that the qual It will be apparent to those skilled in the art, that I have therefore devised a new and novel system for supplying radio frequency energy in any suitable form, to the subscribers loops of standard telephone equipment. I do not desire to be limited to the particular illustrative embodiment of the principles of my invention as disclosed herein, but rather to the spirit and scope of m invention as it will be defined in the appen ed claims, since many details in construction and relative arrangement of parts will readily occur to those skilled in the art. I

What I seek to secure by United States Letters' Patent is:

1. In a si nalling system, the combination with a telep ione cable comprising a plurality of subscribers loops, said loops being 1nsulated from each other, of a tuned grounded antenna within said cable insulated from the loops, a plurality of transmitters associated with said antenna adapted to impress hi h frequency signals of diiferent wave lengt s on said antenna, and a receiver connected to each loop at the subscribers station adapted to select any particular wave length desired the energy on said antenna being transmitted to all the loops through the insulation.

2. In a system for introducing signals into telephone subscribers station, the combination with a telephone cable comprising a plurality of subscribers loops, 0 an antenna within the cable comprising one of said loops, means for delivering high frequency energy to said loop whereby the energy is communicated to all the other loops in the cable, and means for receiving energy from each of said subscribers loopsat his station.

3. In a system for introducing signals nto telephone subscribers stations, thecombmation with a telephone cable comprislng a plurality of subscribers loops, of an antenna comprising one of said loops, means for delivering high frequency energy at several wave lengths to said antenna, and means connected to the other of said loops for receiving any one of these articular wave lengths desired, the energy eing confined to the other loops within the cable.

4. In a system for introducing signals into telephone subscribers station, the combination with a telephone cable comprising a plurality of subscribers loops, of a grounded antenna comprising one of said loops, a plurality of means associated with said antenna for simultaneously delivering high frequency energy to said antenna in different wave lengths, and means at each subscribers sta tion for selecting any desired wave length the energy on said antenna being transmitted to all the other loops in the cable.

In testimony whereof I have hereunto set my hand on this 14th day of July A. D., 1926.

' GEORGE O. SQUIER. 

